Some years ago an internal gear pump was published which is capable of very high pressure and very good volumetric efficiency. Said pump works eccellent in practical application. However, said pump is very complicated and has many parts. In addition, it is not possible to adjust it to medial or low pressure range with good mechanical efficiency. It has an outer thrust body which thrust the outer rotor against the inner rotor under fluid pressure. This provides the tight seal, but it causes friction and consists of many difficult configurated parts, which are expensive in fabrication.
It is therefore the aim and intention of this invention to overcome the machining difficulties of the known internal gear pump and at same time to make the pump of the invention also effective for low and medium pressure range applications.